Fibroblast growth factors (FGFs) are polypeptide mitogens that induce the proliferation of a wide variety of cell types (1). Fibroblast growth factor (FGF)/FGF receptor (FGFR1) signaling plays a crucial role in mesoderm formation and patterning. Studies suggest that FGFR1, among the different FGFRs, may play a role in cardiogenesis. Data point to a nonredundant role for FGFR1-mediated signaling in cardiomyocyte development (2). It has also been shown that during development, FGFR1 is required for the generation of the precursor pool, which gives rise to the auditory sensory epithelium. Data also suggest that FGFR1 might have a distinct later role in intercellular signaling within the differentiating auditory sensory epithelium (3). Highly conserved FGF-D2 and FGF-linker (between D2-D3) interfaces define a general binding site for all FGF-FGFR complexes. Specificity is achieved through interactions between the N-terminal and central regions of FGFs and two loop regions in D3 that are subject to alternative splicing. These structures provide a molecular basis for FGF1 as a universal FGFR ligand and for modulation of FGF-FGFR specificity through primary sequence variations and alternative splicing (4).